Pearlescent additives are commonly used to modify the appearance of personal care compositions. The appearance modification imparted by such additives is influenced by the opacity and shine exhibited by the relevant additive and may range from a highly pearlescence appearance, that is, an iridescent opacity, wherein the pearlizing additive exhibits a high shine, to no pearlescence, that is, a dull or matte opacity, wherein the pearlescent additive exhibits no shine.
Pearlescent additives are typically crystalline materials. The appearance imparted by a pearlescent additive is believed to arise from the crystal morphology of the pearlescent additive. While pearlescent characteristics may be generated in-situ, i.e., by directly adding a pearlescent additive during blending of the product formulation, it is common to add pearlescent additives in the form of a pearlizing concentrate. Use of a pearlizing concentrate allows increased consistency and allows for a reduction in the manufacturing time required for making the finished formulation.
Since the appearance imparted by pearlescent additives is influenced by the opacity and shine characteristics of such additives, it would be beneficial if the opacity and shine characteristics of such additives could be controlled.